JP2513756Y2 - Anti-lock brake system - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] This invention is a two-system control braking system, in which, in particular, the discharge liquid at the time of antilock decompression is made to flow once to a reservoir, and this is supplied by a pump for each system. The present invention relates to an anti-lock brake system that recirculates to the side.

[Conventional technology]

In the circulating anti-lock brake system described above, each of the first and second hydraulic systems independent of each other has an anti-lock control valve and a reservoir that temporarily stores the brake fluid discharged from the wheel cylinder when the anti-lock pressure is reduced. And a pump for pumping out the liquid in the reservoir and returning it to the supply side.

Among these elements, the same brake is used for each wheel for the reservoir, so conventionally the capacity of the reservoir is shortened during a so-called jump mu when suddenly changing from a high μ road to a low μ road. The two systems are set to have the same capacity within a range satisfying the conditions that sufficient decompression can be performed and that the survival system can maintain the minimum required braking force when one system fails.

[Problems to be solved by the device]

Under the condition that the anti-lock control is not prohibited because both pumps of both systems have failed and cannot be detected (this case occurs, for example, when the drive shaft of the pump is broken), the ECU electronic control unit detects When the lock decompression command is issued, the brake fluid discharged from the wheel brakes via the control valve is accumulated in the reservoir. On the other hand, repressurization after depressurization is performed only by the liquid supply from the master cylinder because there is no reflux from the reservoir, and the brake pedal gradually digs in deeply.

For this reason, in conventional systems, the reservoir fills up in a few seconds, further pressure reduction is not possible, wheel locking occurs, and if the reservoir is designed to be large enough, the pedal will reach its limit. If the brake pressure does not rise any further and a high brake pressure is required during the braking, such as when the road is moved to a high μ road, the braking force becomes insufficient and the braking distance is extended, which is a dangerous condition.

Therefore, the present invention proposes a recirculation type anti-lock brake system in which the above-mentioned trouble is avoided even if the recirculation function of the pump is lost, and the braking force and the stability of the vehicle are compatible.

[Means for solving the problem]

The present invention is directed to solving the above-mentioned problems by first and second
The reservoir capacity of the hydraulic system is made different, and regarding the amount of liquid supplied to each hydraulic system at the time of full stroke of the master cylinder, the first hydraulic system is V _a , the second hydraulic system is V _b , and the first hydraulic system is Let V _{1 be} the reservoir capacity of V ₁ and V _{2 be} the reservoir capacity of the second hydraulic system, then V _a ,
In the liquid amount of the V ₁ and V ₂ (V _a -V ₁₎ for V _b obtained predetermined brake pressure, amount of liquid above the liquid of _{(V b -V 2) (V} a -V 1) The brake pressure should be smaller than the brake pressure obtained at.

[Action]

When the anti-lock control is started in a state where the return functions of the two systems have both failed, the second system has a large reservoir capacity, so that decompression is performed without any trouble and wheel locking is avoided.

On the other hand, since the first system has a small reservoir capacity, the reserve capacity for pressurization by the master cylinder remains even after the reservoir is full. Therefore, even if there is a sudden change from the low μ road to the high μ road, The remaining braking force can be used to generate the required braking force.

After the reservoir of the first system is full, the depression of the brake pedal is restricted by the first system, so that the second system cannot repressurize after depressurization, and the insufficient hydraulic pressure is applied to the first system. Since it becomes necessary to cover the situation, it is difficult for the first system to lock the wheels. Further, even if the wheels are locked in the first system, the total number of locked wheels is halved compared to the conventional one, so that the stability of the vehicle is not significantly impaired.

In addition, when one system fails and the hydraulic pressure of that system does not rise, it is detected and the antilock of the other system is prohibited. Therefore, by increasing the reservoir capacity of the second system, It cannot be said that the braking ability is lost only by the second system when the system fails.

〔Example〕

 The attached drawing shows an embodiment of the present invention.

In the figure, 1 is a brake pedal, 2 is a booster that amplifies pedaling force and transmits it to the tandem master cylinder 3, 4 is front wheel brake, 5 is rear wheel brake (additional signals R of 4, 5
L shows the right and left of the wheel), 6 is one hydraulic system connected to 4L and 5R, 7 is the other hydraulic system connected to 4R and 5L, 8 is between each wheel brake and master cylinder Anti-lock control valves provided, 9 and 10 are reservoirs, 11 and 12 are pumps for pumping out the liquid in each reservoir and returning it to the supply side, 13 is 11 and 12
Is a motor for driving, and 14 is a check valve.

The control valve 8 cuts off the communication between the wheel brake and the master cylinder when the antilock decompression command is received from the ECU (not shown) to allow the wheel brake to communicate with the reservoir, and receives the repressurization command from the ECU to turn the wheel brake on. Shut off from reservoir and communicate with master cylinder. In some cases, the wheel brake is cut off from both the master cylinder and the reservoir to maintain the brake fluid pressure on the wheel side.

In this brake system, 6 is the first hydraulic system,
7 is used as a second hydraulic system, and the capacity of the reservoir 9 is designed small and the capacity of 10 is designed large.

The volume V _{1 of the} reservoir 9 needs to be required at the time of a failure at a fluid amount of V _a −V ₁ where V _a is the fluid amount supplied to the first hydraulic system when the master cylinder 3 has a full stroke. The value is such that a minimum braking force can be obtained.

On the other hand, the capacity V _{2 of the} reservoir 10 is set to a value such that the brake pressure becomes sufficiently low with the amount of liquid of V _b −V ₂ and wheel lock does not occur even on the road surface where the assumed friction coefficient (μ) is the lowest. .

Note that V ₁ is the liquid volume of V _a −V ₁ and is 0.3 G even when the other system fails.
It is desirable that the value is such that a deceleration equal to or higher than (G is gravitational acceleration) is obtained.

Also, V ₂ is better to keep the value satisfying the condition of the brake pressure obtained in the liquid volume V _b -V ₂ is avoided wheel lock even road surface mu = 0.1.

Next, the exemplified brake system shows a so-called X piping system in which the right front wheel and the left rear wheel are connected to one system and the left front wheel and the right rear wheel are connected to the other system. In this X piping system, either system may be used as the first system, but in the II piping system in which the two systems are divided into the front two wheels and the rear two wheels, the rear wheel lock is reliably avoided, so that the rear two The system connecting the wheels is the second system, and a large reservoir is installed on this side.
Also, motorcycles are dangerous if the front wheels are locked,
The front wheel side is the second system and a large reservoir is installed on this side.

Even with these piping methods, the capacity V _{1 of the} small reservoir is V _a −V ₁
The value of 0.3G or more is obtained in the liquid long hole shape, while the capacity V _{2 of the} large reservoir is the value at which the vehicle deceleration is 0.1G or less with the amount of liquid of _Vb- V ₂ . If possible, it is desirable to keep the brake pressure at this amount at a value that avoids wheel lock even if the road surface μ = 0.1. If the lock is avoided even on a road surface with a road surface μ of 0.1, the vehicle can be braked stably on an icy road with a very low μ. The brake pressure at this time is roughly 5 kgf / cm ² or less for a four-wheeled vehicle and 3 kgf / cm ² or less for a two-wheeled vehicle.

〔effect〕

As described above, the braking system of this invention is
By making the capacity of the reservoirs provided in the first and second systems different so as to avoid an extreme decrease in braking force due to anti-lock decompression when the reflux function fails and a deterioration in steering performance due to wheel lock, it is possible to prevent vehicle braking. The effect that reliability and safety are enhanced can be obtained.

[Brief description of drawings]

The attached drawing is a circuit diagram showing an embodiment of the present invention. 1 ... Brake pedal, 2 ... Booster, 3 ... Tandem master cylinder, 4 ... Front wheel brake, 5 ... Rear wheel brake, 6 ... First hydraulic system, 7 ... Second hydraulic system, 8 …
… Anti-lock control valve, 9 …… Small reservoir, 10 …… Large reservoir, 11,12 …… Pump, 13 …… Motor, 14 …… Check valve.

Claims (4)

(57) [Scope of utility model registration request] 1. An anti-lock control valve, a reservoir for temporarily storing discharge brake fluid when anti-lock pressure is reduced, and a reservoir having independent first and second hydraulic systems. In a reflux type anti-lock brake system equipped with a pump that pumps out the liquid inside and returns it to the supply side, the reservoir capacities of the first and second hydraulic systems are made different, and each hydraulic system at the time of full stroke of the master cylinder Regarding the amount of liquid supplied to the first hydraulic system, V _a , the second hydraulic system, V _b , the reservoir capacity of the first hydraulic system was V ₁ , and the reservoir capacity of the second hydraulic system was V ₂ . Then V ₁ and V ₂ for V _a and V _b are (V _a
The liquid volume of -V ₁₎ predetermined braking pressure is obtained, (V _b -
The anti-lock brake system is characterized in that the amount of fluid of V ₂ ) is set to a value at which a brake pressure smaller than the brake pressure obtained when the amount of fluid of (V _a −V ₁ ) is obtained. 2. A four-wheeled vehicle, in which either the right front wheel and the left rear wheel or the left front wheel and the right rear wheel are connected to a first hydraulic system and the other is connected to a second hydraulic system, respectively. The antilock brake according to claim 1, wherein the reservoir capacity of the system is set to a value at which a brake pressure with which the vehicle deceleration is 0.1 G (G: gravity acceleration) or less can be obtained with a liquid amount of (V _b -V ₂ ). system. The 3. A two-wheel front of a four-wheel vehicle in the first hydraulic system, the 2 rear wheels respectively connected to the second hydraulic system, the reservoir capacity of the second hydraulic system (V _b -V ₂₎ The antilock brake system according to claim 1, wherein the brake pressure is set to a value such that the vehicle deceleration becomes 0.1 G or less with the amount of the liquid. 4. A front wheel of a two-wheeled vehicle is a second hydraulic system, and a rear wheel is a first hydraulic system.
Connect to the hydraulic system respectively and set the reservoir capacity of the second hydraulic system to (V _b
The antilock brake system according to claim 1, wherein the brake pressure is set to a value such that the vehicle deceleration becomes 0.1 G or less with a liquid volume of -V ₂ ).